project-euler/Sidef/027 Quadratic primes.sf

#!/usr/bin/ruby

# Daniel "Trizen" Șuteu
# License: GPLv3
# Date: 27 January 2017
# https://github.com/trizen

# https://projecteuler.net/problem=27

# Runtime: 4.024s

var limit = 1000

var m = 0
var p = 0
var q = 0

var primes = limit.primes

for a in primes, b in primes {

    with (^Inf -> first_by {|k| !is_prime(k*k + a*k + b) }) { |n|
        if (n > m) {
            (m, p, q) = (n, a, b)
        }
    }

    with (^Inf -> first_by {|k| !is_prime(k*k - a*k + b) }) { |n|
        if (n > m) {
            (m, p, q) = (n, -a, b)
        }
    }
}

say "n^2 + #{p}*n + #{q} for 0 <= n < #{m}"
say "#{p} * #{q} = #{p * q}"